Analysis of Sulfur Compounds in a Petroleum Fraction using Agilent J&W DB-Sulfur SCD GC Column and Inert Flow Path

Importance of the topic

Monitoring sulfur compounds in petroleum fractions is critical for protecting downstream catalysts, meeting environmental regulations, and ensuring fuel quality. Detailed speciation of sulfur components helps petrochemical and refining industries identify problematic species, optimize process conditions, and prevent catalyst poisoning and engine corrosion.

Objectives and overview of the study

This application note describes the evaluation of an Agilent J&W DB-Sulfur SCD GC column combined with an Agilent Inert Flow Path gas chromatograph and sulfur chemiluminescence detector (SCD). The study follows ASTM D5623 to selectively identify and quantify twenty volatile sulfur compounds in gasoline matrices, including hydrogen sulfide and carbonyl sulfide, without requiring cryogenic cooling.

Methodology and instrumentation used

The experimental system comprised:

• Agilent 7890 Gas Chromatograph with Inert Flow Path split/splitless inlet
• Agilent 355 Dual Plasma Sulfur Chemiluminescence Detector
• Agilent 7683 Automatic Liquid Sampler
• Agilent J&W DB-Sulfur SCD column (60 m × 0.32 mm, 4.2 µm film)
• Ultra Inert inlet liner and gold seal to minimize adsorption
• Helium carrier gas at 2.8 mL/min; injector at 275 °C, split ratio 10:1; oven program from 35 °C to 250 °C at 10 °C/min
• SCD conditions: burner 800 °C, reaction cell 5 Torr, hydrogen 40 mL/min, air 60 mL/min

Standard solutions of twenty sulfur compounds were prepared in toluene at varying concentrations (0.1–50 ppm) with diphenyl sulfide as the internal standard. A cracked gasoline sample spiked with internal standard was used to demonstrate real‐world performance.

Main results and discussion

Key findings include:

• Baseline separation of all twenty sulfur species, notably hydrogen sulfide and carbonyl sulfide at ambient initial oven temperature, eliminating the need for cryogenic cooling.
• Excellent linearity (R² > 0.997) across recommended concentration ranges, with equimolar SCD response.
• Signal‐to‐noise ratios above 4 for most compounds at 0.1 mg/kg (0.01 ng on column).
• Repeatability (RSD) below 5% at low, mid and high concentration levels for all analytes.
• Application to a cracked gasoline sample achieved quantitation of individual sulfur species (e.g., thiophene 30.8 mg/kg, 2-methylthiophene 8.7 mg/kg) and total sulfur with RSD < 5%.

Benefits and practical applications of the method

This GC/SCD approach provides high selectivity and sensitivity for sulfur speciation in complex petroleum matrices. The inert flow path and low‐bleed DB-Sulfur SCD column ensure minimal adsorption and detector contamination, supporting long‐term stability. The elimination of cryogenic cooling simplifies instrumentation and reduces operational costs.

Future trends and applications

Emerging directions include combining SCD with mass spectrometry for structural confirmation, adapting the method to heavier fuel cuts and alternative energy feedstocks, and integrating automated sample preparation for high‐throughput quality control. Further optimization of column phases may expand detection of sulfur‐nitrogen heterocycles and emerging environmental contaminants.

Conclusion

The Agilent Inert Flow Path GC/SCD system equipped with the J&W DB-Sulfur SCD column delivers reliable, reproducible, and sensitive analysis of volatile sulfur compounds in gasoline, meeting ASTM D5623 requirements. Its robust performance and simplified cooling requirements make it a valuable tool for refining, petrochemical, and quality-assurance laboratories.

References

• ASTM D5623-94. Standard Test Method for Sulfur Compounds in Light Petroleum Liquids by Gas Chromatography and Sulfur Selective Detection. ASTM International, 1994.
• Liu W., Morales M. Detection of Sulfur Compounds According to ASTM D5623 in Gasoline with Agilent’s Dual Plasma Sulfur Chemiluminescence Detector and an Agilent 7890A GC. Agilent Technologies Application Note, 2008.
• Agilent Technologies. Agilent 355 Sulfur Chemiluminescence Detector: Odorants and Other Sulfur Compounds in Liquefied Petroleum and Natural Gases. Technical Overview, 2007.